The new iPod Touch is a gorgeous device, more so than the iPhone. Despite the fixed memory, I plan to eventually pick one up. Otherwise, I own 2 different iPod Nano's... the latest being a 6th generation. It's the ideal workout music device, and it surprised me that Apple abandoned the design, opting for the limited operating system in a larger 5th generation form factor (no built-in clip either).
There are some things in favor of fixed memory, in that there's no additional port to collect debris, compromise the internals, and no card to worry about losing. Also, it's great to see how Android continues to improve while not getting too bloated (and you can always opt for rooting, to install a leaner version offered for free by industrious developers), so with those few devices lacking removable memory it's not a huge handicap.